Blender
by Xingyu Zhou 
set units to millimeters:
shift + a: add object
ctrl + middle mouse: view zoom
shift + middle mouse: view pan
middle mouse: view rotate
tab: toggle edit mode (EM) and object mode (OM)
EM | e > esc: extrude (拉伸)
自定义的表示法：
EM | e > esc表示在EM下，按e键，然后按esc键。shift + a表示同时按下shift和a键。
x: delete
a: select all
to see objects clearly:
n: toggle right panel
shift + select: add to selection (多选)
place 3d cursor at the middle of selected vertices:
place 3d cursor at the intersection of two lines:
toggle x-ray in order to select back vertices.
show some useful overlays:
merge vertices:
snap (吸附) to vertices and messure (hold ctrl to snap):
filet (圆角) and chamfer (倒角):
除了倒角的 segment 设置为 1 外，其他尽量使用偶数。
place 3d cursor in relation to selected vertices:
f: fill face (填充面)
alt + click: select edge loop (边环)
edge loop is a continuous selection of edges that form a loop. (also works for faces and vertices)
fill the face with holes:
shift + d > esc: duplicate
shift + g: select grouped
join and part objects:
- 设置完每个对象的 material 后，就可以 part by material 了。
parent objects:
- 选择父对象不会选择子对象，但对父对象的操作会影响子对象。
为对象添加 material 颜色，方便区分：
use addon measureit to measure:
- 相对于自带的测量工具，好处有二。一是一旦选择好测量的对象，当该对象发生变化时，测量也会自动更新。二是可以自定义精确度。
use addon align tools to align objects:
- 对齐操作作用于对象的原点（origin）
- 将所有选中的对象对齐到激活的对象（active object）
- 在 OM 下，移动对象会连带原点一起移动，但在 EM 下，移动对象不会连带原点一起移动。实际上在 EM 下，原点是不会受到任何影响的
flip normal (翻转法线的方向)：
alt + e > extrude along normals > s: extrude along normals and keep right offset
move origin to 3d cursor:
shift + right clickto move 3d cursorshift + right click > move + ctrlto snap 3d cursor- when move 3d cursor to a face, it will snap to that face automatically
shift + s: 3d cursor pie menu
q: open quick favorites menu
add operation to quick favorites:
right click > add to quick favorites
选取对侧到边按 f 即可填充面
inset (内缩):
在该平面的中心打个孔：
modifier has to make sure that normals are correct, so it's good to check normals before adding modifier
modifier options 确定好后需要应用 (
cmd + a) 才能生效
使用 display as bounds 的好处在于移动物体可以实时看到 modifier 的效果
或者使用 addon
booltool，实现相同效果
do scale (缩放) in edit mode, and don't do scale in object mode, cause it will mess up the scale of the object:
this could be a reason why boolean modifier doesn't work
if you do scale in object mode, you need to apply scale bycmd + a
alt + d: linked duplicate
linked object is a copy of the original object, and it will change when the original object changes.
这在制作 joint (关节) 时非常有用：
object orientation is not linked, only object shape is linked.
bevel (斜角) modifier:
使用 vertex group 控制斜角作用范围有时候会不符合我们的预期，比如：
edge offset:
